The biggest diet killers have almost four times that amount! And a good dose of hidden fat, to boot. That's anything but cool when you're trying to keep daily calories -- from drink and food -- at no more than 1,500 a day for weight loss. "Smoothies aren't necessarily any healthier than soda," says Bethany Thayer, nutritionist with the Henry Ford Health System. "I say make your own -- with frozen fruit and fat-free vanilla yogurt!"

Here are 5 more fast food smoothies that are egregiously unhealthy -- something to keep in mind when pulling up at the drive-through this summer.

1. Sonic: Strawberry Smoothie (Regular size)

On first glance this non-fat beverage seems innocuous; but its 542 calories and 99 grams of sugar can really sneak up on you. A better choice would be one of the Low-Cal Limeades.

2. Planet Smoothie: PBJ (16 oz.)

It's a tad unfair to pick on Planet Smoothie because the chain has so many more moderate offerings. But we can't ignore the PBJ Smoothie with 500 calories and 16 grams of fat.

3. Orange Julius: Cocoa Latte Swirl (20 oz.)

With a whopping 960 calories and 23 grams of fat, not to mention 119 grams of sugar and 870 milligrams of sodium, this premium smoothie is one for the record books. The upside? You won't have to eat the rest of the day.

4. Smoothie King: Peanut Power Plus Grape (20 oz.)

The website lists this smoothie under "Indulge" and it's not kidding: This baby's got 749 calories and 22 grams of fat. Steer clear of this treat, and order one from the "Trim Down" category.

5. Tropical Smoothie: Caramel Cream Coffee Smoothie (24 oz.)

If you're watching your weight, stick to the low-fat options and skip the coffee smoothies altogether; this particular drink has 791 calories and 11.2 grams of fat.

.

Which fast food smoothie is your favorite? Did you have any idea they could be so unhealthy?